Implement changes to MSC2285 (hidden read receipts) (#12168)

* Changes hidden read receipts to be a separate receipt type
  (instead of a field on `m.read`).
* Updates the `/receipts` endpoint to accept `m.fully_read`.

3 files changed, 449 insertions, 79 deletions

diff --git a/tests/handlers/test_receipts.py b/tests/handlers/test_receipts.py
index 65ab7db0c8..c12a9120f0 100644
--- a/tests/handlers/test_receipts.py
+++ b/tests/handlers/test_receipts.py
@@ -15,7 +15,7 @@
 
 from typing import List
 
-from synapse.api.constants import ReadReceiptEventFields, ReceiptTypes
+from synapse.api.constants import ReceiptTypes
 from synapse.types import JsonDict
 
 from tests import unittest
@@ -25,20 +25,15 @@ class ReceiptsTestCase(unittest.HomeserverTestCase):
     def prepare(self, reactor, clock, hs):
         self.event_source = hs.get_event_sources().sources.receipt
 
-    # In the first param of _test_filters_hidden we use "hidden" instead of
-    # ReadReceiptEventFields.MSC2285_HIDDEN. We do this because we're mocking
-    # the data from the database which doesn't use the prefix
-
     def test_filters_out_hidden_receipt(self):
         self._test_filters_hidden(
             [
                 {
                     "content": {
                         "$1435641916114394fHBLK:matrix.org": {
-                            ReceiptTypes.READ: {
+                            ReceiptTypes.READ_PRIVATE: {
                                 "@rikj:jki.re": {
                                     "ts": 1436451550453,
-                                    "hidden": True,
                                 }
                             }
                         }
@@ -50,58 +45,23 @@ class ReceiptsTestCase(unittest.HomeserverTestCase):
             [],
         )
 
-    def test_does_not_filter_out_our_hidden_receipt(self):
-        self._test_filters_hidden(
-            [
-                {
-                    "content": {
-                        "$1435641916hfgh4394fHBLK:matrix.org": {
-                            ReceiptTypes.READ: {
-                                "@me:server.org": {
-                                    "ts": 1436451550453,
-                                    "hidden": True,
-                                },
-                            }
-                        }
-                    },
-                    "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
-                    "type": "m.receipt",
-                }
-            ],
-            [
-                {
-                    "content": {
-                        "$1435641916hfgh4394fHBLK:matrix.org": {
-                            ReceiptTypes.READ: {
-                                "@me:server.org": {
-                                    "ts": 1436451550453,
-                                    ReadReceiptEventFields.MSC2285_HIDDEN: True,
-                                },
-                            }
-                        }
-                    },
-                    "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
-                    "type": "m.receipt",
-                }
-            ],
-        )
-
     def test_filters_out_hidden_receipt_and_ignores_rest(self):
         self._test_filters_hidden(
             [
                 {
                     "content": {
                         "$1dgdgrd5641916114394fHBLK:matrix.org": {
-                            ReceiptTypes.READ: {
+                            ReceiptTypes.READ_PRIVATE: {
                                 "@rikj:jki.re": {
                                     "ts": 1436451550453,
-                                    "hidden": True,
                                 },
+                            },
+                            ReceiptTypes.READ: {
                                 "@user:jki.re": {
                                     "ts": 1436451550453,
                                 },
-                            }
-                        }
+                            },
+                        },
                     },
                     "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
                     "type": "m.receipt",
@@ -130,10 +90,9 @@ class ReceiptsTestCase(unittest.HomeserverTestCase):
                 {
                     "content": {
                         "$14356419edgd14394fHBLK:matrix.org": {
-                            ReceiptTypes.READ: {
+                            ReceiptTypes.READ_PRIVATE: {
                                 "@rikj:jki.re": {
                                     "ts": 1436451550453,
-                                    "hidden": True,
                                 },
                             }
                         },
@@ -223,7 +182,6 @@ class ReceiptsTestCase(unittest.HomeserverTestCase):
             [
                 {
                     "content": {
-                        "$143564gdfg6114394fHBLK:matrix.org": {},
                         "$1435641916114394fHBLK:matrix.org": {
                             ReceiptTypes.READ: {
                                 "@user:jki.re": {
@@ -244,10 +202,9 @@ class ReceiptsTestCase(unittest.HomeserverTestCase):
                 {
                     "content": {
                         "$14356419edgd14394fHBLK:matrix.org": {
-                            ReceiptTypes.READ: {
+                            ReceiptTypes.READ_PRIVATE: {
                                 "@rikj:jki.re": {
                                     "ts": 1436451550453,
-                                    "hidden": True,
                                 },
                             }
                         },
@@ -306,7 +263,73 @@ class ReceiptsTestCase(unittest.HomeserverTestCase):
                     "type": "m.receipt",
                 },
             ],
-            [],
+            [
+                {
+                    "content": {
+                        "$14356419edgd14394fHBLK:matrix.org": {
+                            ReceiptTypes.READ: {
+                                "@rikj:jki.re": "string",
+                            }
+                        },
+                    },
+                    "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
+                    "type": "m.receipt",
+                },
+            ],
+        )
+
+    def test_leaves_our_hidden_and_their_public(self):
+        self._test_filters_hidden(
+            [
+                {
+                    "content": {
+                        "$1dgdgrd5641916114394fHBLK:matrix.org": {
+                            ReceiptTypes.READ_PRIVATE: {
+                                "@me:server.org": {
+                                    "ts": 1436451550453,
+                                },
+                            },
+                            ReceiptTypes.READ: {
+                                "@rikj:jki.re": {
+                                    "ts": 1436451550453,
+                                },
+                            },
+                            "a.receipt.type": {
+                                "@rikj:jki.re": {
+                                    "ts": 1436451550453,
+                                },
+                            },
+                        },
+                    },
+                    "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
+                    "type": "m.receipt",
+                }
+            ],
+            [
+                {
+                    "content": {
+                        "$1dgdgrd5641916114394fHBLK:matrix.org": {
+                            ReceiptTypes.READ_PRIVATE: {
+                                "@me:server.org": {
+                                    "ts": 1436451550453,
+                                },
+                            },
+                            ReceiptTypes.READ: {
+                                "@rikj:jki.re": {
+                                    "ts": 1436451550453,
+                                },
+                            },
+                            "a.receipt.type": {
+                                "@rikj:jki.re": {
+                                    "ts": 1436451550453,
+                                },
+                            },
+                        }
+                    },
+                    "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
+                    "type": "m.receipt",
+                }
+            ],
         )
 
     def _test_filters_hidden(
diff --git a/tests/replication/slave/storage/test_receipts.py b/tests/replication/slave/storage/test_receipts.py
index de19e75b9d..5bbbd5fbcb 100644
--- a/tests/replication/slave/storage/test_receipts.py
+++ b/tests/replication/slave/storage/test_receipts.py
@@ -14,26 +14,246 @@
 
 from synapse.api.constants import ReceiptTypes
 from synapse.replication.slave.storage.receipts import SlavedReceiptsStore
+from synapse.types import UserID, create_requester
+
+from tests.test_utils.event_injection import create_event
 
 from ._base import BaseSlavedStoreTestCase
 
-USER_ID = "@feeling:blue"
-ROOM_ID = "!room:blue"
-EVENT_ID = "$event:blue"
+OTHER_USER_ID = "@other:test"
+OUR_USER_ID = "@our:test"
 
 
 class SlavedReceiptTestCase(BaseSlavedStoreTestCase):
 
     STORE_TYPE = SlavedReceiptsStore
 
-    def test_receipt(self):
-        self.check("get_receipts_for_user", [USER_ID, ReceiptTypes.READ], {})
+    def prepare(self, reactor, clock, homeserver):
+        super().prepare(reactor, clock, homeserver)
+        self.room_creator = homeserver.get_room_creation_handler()
+        self.persist_event_storage = self.hs.get_storage().persistence
+
+        # Create a test user
+        self.ourUser = UserID.from_string(OUR_USER_ID)
+        self.ourRequester = create_requester(self.ourUser)
+
+        # Create a second test user
+        self.otherUser = UserID.from_string(OTHER_USER_ID)
+        self.otherRequester = create_requester(self.otherUser)
+
+        # Create a test room
+        info, _ = self.get_success(self.room_creator.create_room(self.ourRequester, {}))
+        self.room_id1 = info["room_id"]
+
+        # Create a second test room
+        info, _ = self.get_success(self.room_creator.create_room(self.ourRequester, {}))
+        self.room_id2 = info["room_id"]
+
+        # Join the second user to the first room
+        memberEvent, memberEventContext = self.get_success(
+            create_event(
+                self.hs,
+                room_id=self.room_id1,
+                type="m.room.member",
+                sender=self.otherRequester.user.to_string(),
+                state_key=self.otherRequester.user.to_string(),
+                content={"membership": "join"},
+            )
+        )
+        self.get_success(
+            self.persist_event_storage.persist_event(memberEvent, memberEventContext)
+        )
+
+        # Join the second user to the second room
+        memberEvent, memberEventContext = self.get_success(
+            create_event(
+                self.hs,
+                room_id=self.room_id2,
+                type="m.room.member",
+                sender=self.otherRequester.user.to_string(),
+                state_key=self.otherRequester.user.to_string(),
+                content={"membership": "join"},
+            )
+        )
+        self.get_success(
+            self.persist_event_storage.persist_event(memberEvent, memberEventContext)
+        )
+
+    def test_return_empty_with_no_data(self):
+        res = self.get_success(
+            self.master_store.get_receipts_for_user(
+                OUR_USER_ID, [ReceiptTypes.READ, ReceiptTypes.READ_PRIVATE]
+            )
+        )
+        self.assertEqual(res, {})
+
+        res = self.get_success(
+            self.master_store.get_receipts_for_user_with_orderings(
+                OUR_USER_ID,
+                [ReceiptTypes.READ, ReceiptTypes.READ_PRIVATE],
+            )
+        )
+        self.assertEqual(res, {})
+
+        res = self.get_success(
+            self.master_store.get_last_receipt_event_id_for_user(
+                OUR_USER_ID,
+                self.room_id1,
+                [ReceiptTypes.READ, ReceiptTypes.READ_PRIVATE],
+            )
+        )
+        self.assertEqual(res, None)
+
+    def test_get_receipts_for_user(self):
+        # Send some events into the first room
+        event1_1_id = self.create_and_send_event(
+            self.room_id1, UserID.from_string(OTHER_USER_ID)
+        )
+        event1_2_id = self.create_and_send_event(
+            self.room_id1, UserID.from_string(OTHER_USER_ID)
+        )
+
+        # Send public read receipt for the first event
+        self.get_success(
+            self.master_store.insert_receipt(
+                self.room_id1, ReceiptTypes.READ, OUR_USER_ID, [event1_1_id], {}
+            )
+        )
+        # Send private read receipt for the second event
         self.get_success(
             self.master_store.insert_receipt(
-                ROOM_ID, ReceiptTypes.READ, USER_ID, [EVENT_ID], {}
+                self.room_id1, ReceiptTypes.READ_PRIVATE, OUR_USER_ID, [event1_2_id], {}
+            )
+        )
+
+        # Test we get the latest event when we want both private and public receipts
+        res = self.get_success(
+            self.master_store.get_receipts_for_user(
+                OUR_USER_ID, [ReceiptTypes.READ, ReceiptTypes.READ_PRIVATE]
             )
         )
-        self.replicate()
-        self.check(
-            "get_receipts_for_user", [USER_ID, ReceiptTypes.READ], {ROOM_ID: EVENT_ID}
+        self.assertEqual(res, {self.room_id1: event1_2_id})
+
+        # Test we get the older event when we want only public receipt
+        res = self.get_success(
+            self.master_store.get_receipts_for_user(OUR_USER_ID, [ReceiptTypes.READ])
+        )
+        self.assertEqual(res, {self.room_id1: event1_1_id})
+
+        # Test we get the latest event when we want only the public receipt
+        res = self.get_success(
+            self.master_store.get_receipts_for_user(
+                OUR_USER_ID, [ReceiptTypes.READ_PRIVATE]
+            )
+        )
+        self.assertEqual(res, {self.room_id1: event1_2_id})
+
+        # Test receipt updating
+        self.get_success(
+            self.master_store.insert_receipt(
+                self.room_id1, ReceiptTypes.READ, OUR_USER_ID, [event1_2_id], {}
+            )
+        )
+        res = self.get_success(
+            self.master_store.get_receipts_for_user(OUR_USER_ID, [ReceiptTypes.READ])
+        )
+        self.assertEqual(res, {self.room_id1: event1_2_id})
+
+        # Send some events into the second room
+        event2_1_id = self.create_and_send_event(
+            self.room_id2, UserID.from_string(OTHER_USER_ID)
+        )
+
+        # Test new room is reflected in what the method returns
+        self.get_success(
+            self.master_store.insert_receipt(
+                self.room_id2, ReceiptTypes.READ_PRIVATE, OUR_USER_ID, [event2_1_id], {}
+            )
+        )
+        res = self.get_success(
+            self.master_store.get_receipts_for_user(
+                OUR_USER_ID, [ReceiptTypes.READ, ReceiptTypes.READ_PRIVATE]
+            )
+        )
+        self.assertEqual(res, {self.room_id1: event1_2_id, self.room_id2: event2_1_id})
+
+    def test_get_last_receipt_event_id_for_user(self):
+        # Send some events into the first room
+        event1_1_id = self.create_and_send_event(
+            self.room_id1, UserID.from_string(OTHER_USER_ID)
+        )
+        event1_2_id = self.create_and_send_event(
+            self.room_id1, UserID.from_string(OTHER_USER_ID)
+        )
+
+        # Send public read receipt for the first event
+        self.get_success(
+            self.master_store.insert_receipt(
+                self.room_id1, ReceiptTypes.READ, OUR_USER_ID, [event1_1_id], {}
+            )
+        )
+        # Send private read receipt for the second event
+        self.get_success(
+            self.master_store.insert_receipt(
+                self.room_id1, ReceiptTypes.READ_PRIVATE, OUR_USER_ID, [event1_2_id], {}
+            )
+        )
+
+        # Test we get the latest event when we want both private and public receipts
+        res = self.get_success(
+            self.master_store.get_last_receipt_event_id_for_user(
+                OUR_USER_ID,
+                self.room_id1,
+                [ReceiptTypes.READ, ReceiptTypes.READ_PRIVATE],
+            )
+        )
+        self.assertEqual(res, event1_2_id)
+
+        # Test we get the older event when we want only public receipt
+        res = self.get_success(
+            self.master_store.get_last_receipt_event_id_for_user(
+                OUR_USER_ID, self.room_id1, [ReceiptTypes.READ]
+            )
+        )
+        self.assertEqual(res, event1_1_id)
+
+        # Test we get the latest event when we want only the private receipt
+        res = self.get_success(
+            self.master_store.get_last_receipt_event_id_for_user(
+                OUR_USER_ID, self.room_id1, [ReceiptTypes.READ_PRIVATE]
+            )
+        )
+        self.assertEqual(res, event1_2_id)
+
+        # Test receipt updating
+        self.get_success(
+            self.master_store.insert_receipt(
+                self.room_id1, ReceiptTypes.READ, OUR_USER_ID, [event1_2_id], {}
+            )
+        )
+        res = self.get_success(
+            self.master_store.get_last_receipt_event_id_for_user(
+                OUR_USER_ID, self.room_id1, [ReceiptTypes.READ]
+            )
+        )
+        self.assertEqual(res, event1_2_id)
+
+        # Send some events into the second room
+        event2_1_id = self.create_and_send_event(
+            self.room_id2, UserID.from_string(OTHER_USER_ID)
+        )
+
+        # Test new room is reflected in what the method returns
+        self.get_success(
+            self.master_store.insert_receipt(
+                self.room_id2, ReceiptTypes.READ_PRIVATE, OUR_USER_ID, [event2_1_id], {}
+            )
+        )
+        res = self.get_success(
+            self.master_store.get_last_receipt_event_id_for_user(
+                OUR_USER_ID,
+                self.room_id2,
+                [ReceiptTypes.READ, ReceiptTypes.READ_PRIVATE],
+            )
         )
+        self.assertEqual(res, event2_1_id)
diff --git a/tests/rest/client/test_sync.py b/tests/rest/client/test_sync.py
index cb765455c1..67c94dd18f 100644
--- a/tests/rest/client/test_sync.py
+++ b/tests/rest/client/test_sync.py
@@ -23,7 +23,6 @@ import synapse.rest.admin
 from synapse.api.constants import (
     EventContentFields,
     EventTypes,
-    ReadReceiptEventFields,
     ReceiptTypes,
     RelationTypes,
 )
@@ -347,7 +346,7 @@ class SyncKnockTestCase(
         # Knock on a room
         channel = self.make_request(
             "POST",
-            "/_matrix/client/r0/knock/%s" % (self.room_id,),
+            f"/_matrix/client/r0/knock/{self.room_id}",
             b"{}",
             self.knocker_tok,
         )
@@ -412,18 +411,79 @@ class ReadReceiptsTestCase(unittest.HomeserverTestCase):
         # Send a message as the first user
         res = self.helper.send(self.room_id, body="hello", tok=self.tok)
 
-        # Send a read receipt to tell the server the first user's message was read
-        body = json.dumps({ReadReceiptEventFields.MSC2285_HIDDEN: True}).encode("utf8")
+        # Send a private read receipt to tell the server the first user's message was read
         channel = self.make_request(
             "POST",
-            "/rooms/%s/receipt/m.read/%s" % (self.room_id, res["event_id"]),
-            body,
+            f"/rooms/{self.room_id}/receipt/org.matrix.msc2285.read.private/{res['event_id']}",
+            {},
             access_token=self.tok2,
         )
         self.assertEqual(channel.code, 200)
 
-        # Test that the first user can't see the other user's hidden read receipt
-        self.assertEqual(self._get_read_receipt(), None)
+        # Test that the first user can't see the other user's private read receipt
+        self.assertIsNone(self._get_read_receipt())
+
+    @override_config({"experimental_features": {"msc2285_enabled": True}})
+    def test_public_receipt_can_override_private(self) -> None:
+        """
+        Sending a public read receipt to the same event which has a private read
+        receipt should cause that receipt to become public.
+        """
+        # Send a message as the first user
+        res = self.helper.send(self.room_id, body="hello", tok=self.tok)
+
+        # Send a private read receipt
+        channel = self.make_request(
+            "POST",
+            f"/rooms/{self.room_id}/receipt/{ReceiptTypes.READ_PRIVATE}/{res['event_id']}",
+            {},
+            access_token=self.tok2,
+        )
+        self.assertEqual(channel.code, 200)
+        self.assertIsNone(self._get_read_receipt())
+
+        # Send a public read receipt
+        channel = self.make_request(
+            "POST",
+            f"/rooms/{self.room_id}/receipt/{ReceiptTypes.READ}/{res['event_id']}",
+            {},
+            access_token=self.tok2,
+        )
+        self.assertEqual(channel.code, 200)
+
+        # Test that we did override the private read receipt
+        self.assertNotEqual(self._get_read_receipt(), None)
+
+    @override_config({"experimental_features": {"msc2285_enabled": True}})
+    def test_private_receipt_cannot_override_public(self) -> None:
+        """
+        Sending a private read receipt to the same event which has a public read
+        receipt should cause no change.
+        """
+        # Send a message as the first user
+        res = self.helper.send(self.room_id, body="hello", tok=self.tok)
+
+        # Send a public read receipt
+        channel = self.make_request(
+            "POST",
+            f"/rooms/{self.room_id}/receipt/{ReceiptTypes.READ}/{res['event_id']}",
+            {},
+            access_token=self.tok2,
+        )
+        self.assertEqual(channel.code, 200)
+        self.assertNotEqual(self._get_read_receipt(), None)
+
+        # Send a private read receipt
+        channel = self.make_request(
+            "POST",
+            f"/rooms/{self.room_id}/receipt/{ReceiptTypes.READ_PRIVATE}/{res['event_id']}",
+            {},
+            access_token=self.tok2,
+        )
+        self.assertEqual(channel.code, 200)
+
+        # Test that we didn't override the public read receipt
+        self.assertIsNone(self._get_read_receipt())
 
     @parameterized.expand(
         [
@@ -455,7 +515,7 @@ class ReadReceiptsTestCase(unittest.HomeserverTestCase):
         # Send a read receipt for this message with an empty body
         channel = self.make_request(
             "POST",
-            "/rooms/%s/receipt/m.read/%s" % (self.room_id, res["event_id"]),
+            f"/rooms/{self.room_id}/receipt/m.read/{res['event_id']}",
             access_token=self.tok2,
             custom_headers=[("User-Agent", user_agent)],
         )
@@ -479,6 +539,9 @@ class ReadReceiptsTestCase(unittest.HomeserverTestCase):
         # Store the next batch for the next request.
         self.next_batch = channel.json_body["next_batch"]
 
+        if channel.json_body.get("rooms", None) is None:
+            return None
+
         # Return the read receipt
         ephemeral_events = channel.json_body["rooms"]["join"][self.room_id][
             "ephemeral"
@@ -499,7 +562,10 @@ class UnreadMessagesTestCase(unittest.HomeserverTestCase):
 
     def default_config(self) -> JsonDict:
         config = super().default_config()
-        config["experimental_features"] = {"msc2654_enabled": True}
+        config["experimental_features"] = {
+            "msc2654_enabled": True,
+            "msc2285_enabled": True,
+        }
         return config
 
     def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
@@ -564,7 +630,7 @@ class UnreadMessagesTestCase(unittest.HomeserverTestCase):
         body = json.dumps({ReceiptTypes.READ: res["event_id"]}).encode("utf8")
         channel = self.make_request(
             "POST",
-            "/rooms/%s/read_markers" % self.room_id,
+            f"/rooms/{self.room_id}/read_markers",
             body,
             access_token=self.tok,
         )
@@ -578,11 +644,10 @@ class UnreadMessagesTestCase(unittest.HomeserverTestCase):
         self._check_unread_count(1)
 
         # Send a read receipt to tell the server we've read the latest event.
-        body = json.dumps({ReadReceiptEventFields.MSC2285_HIDDEN: True}).encode("utf8")
         channel = self.make_request(
             "POST",
-            "/rooms/%s/receipt/m.read/%s" % (self.room_id, res["event_id"]),
-            body,
+            f"/rooms/{self.room_id}/receipt/org.matrix.msc2285.read.private/{res['event_id']}",
+            {},
             access_token=self.tok,
         )
         self.assertEqual(channel.code, 200, channel.json_body)
@@ -644,13 +709,73 @@ class UnreadMessagesTestCase(unittest.HomeserverTestCase):
         self._check_unread_count(4)
 
         # Check that tombstone events changes increase the unread counter.
-        self.helper.send_state(
+        res1 = self.helper.send_state(
             self.room_id,
             EventTypes.Tombstone,
             {"replacement_room": "!someroom:test"},
             tok=self.tok2,
         )
         self._check_unread_count(5)
+        res2 = self.helper.send(self.room_id, "hello", tok=self.tok2)
+
+        # Make sure both m.read and org.matrix.msc2285.read.private advance
+        channel = self.make_request(
+            "POST",
+            f"/rooms/{self.room_id}/receipt/m.read/{res1['event_id']}",
+            {},
+            access_token=self.tok,
+        )
+        self.assertEqual(channel.code, 200, channel.json_body)
+        self._check_unread_count(1)
+
+        channel = self.make_request(
+            "POST",
+            f"/rooms/{self.room_id}/receipt/org.matrix.msc2285.read.private/{res2['event_id']}",
+            {},
+            access_token=self.tok,
+        )
+        self.assertEqual(channel.code, 200, channel.json_body)
+        self._check_unread_count(0)
+
+    # We test for both receipt types that influence notification counts
+    @parameterized.expand([ReceiptTypes.READ, ReceiptTypes.READ_PRIVATE])
+    def test_read_receipts_only_go_down(self, receipt_type: ReceiptTypes) -> None:
+        # Join the new user
+        self.helper.join(room=self.room_id, user=self.user2, tok=self.tok2)
+
+        # Send messages
+        res1 = self.helper.send(self.room_id, "hello", tok=self.tok2)
+        res2 = self.helper.send(self.room_id, "hello", tok=self.tok2)
+
+        # Read last event
+        channel = self.make_request(
+            "POST",
+            f"/rooms/{self.room_id}/receipt/{receipt_type}/{res2['event_id']}",
+            {},
+            access_token=self.tok,
+        )
+        self.assertEqual(channel.code, 200, channel.json_body)
+        self._check_unread_count(0)
+
+        # Make sure neither m.read nor org.matrix.msc2285.read.private make the
+        # read receipt go up to an older event
+        channel = self.make_request(
+            "POST",
+            f"/rooms/{self.room_id}/receipt/org.matrix.msc2285.read.private/{res1['event_id']}",
+            {},
+            access_token=self.tok,
+        )
+        self.assertEqual(channel.code, 200, channel.json_body)
+        self._check_unread_count(0)
+
+        channel = self.make_request(
+            "POST",
+            f"/rooms/{self.room_id}/receipt/m.read/{res1['event_id']}",
+            {},
+            access_token=self.tok,
+        )
+        self.assertEqual(channel.code, 200, channel.json_body)
+        self._check_unread_count(0)
 
     def _check_unread_count(self, expected_count: int) -> None:
         """Syncs and compares the unread count with the expected value."""
@@ -663,9 +788,11 @@ class UnreadMessagesTestCase(unittest.HomeserverTestCase):
 
         self.assertEqual(channel.code, 200, channel.json_body)
 
-        room_entry = channel.json_body["rooms"]["join"][self.room_id]
+        room_entry = (
+            channel.json_body.get("rooms", {}).get("join", {}).get(self.room_id, {})
+        )
         self.assertEqual(
-            room_entry["org.matrix.msc2654.unread_count"],
+            room_entry.get("org.matrix.msc2654.unread_count", 0),
             expected_count,
             room_entry,
         )